Conventional electric roller shutter contains: a holder for fixing a tube on a door, plural connecting pieces connected together to form a door plate, and a rotatable wheel mounted on the door plate, wherein the door plate is guided by two guiding grooves on two sides of the door, and an electric motor drives the rotatable wheel to roll and unroll the door plate, thus closing and opening the electric roller shutter.
However, the electric roller shutter is manufactured based on a customized length, so the electric roller shutter cannot be produced at large quantity.
Furthermore, a sensor is fixed on a rail of the door so that when the electric roller shutter is rolled or unrolled at a predetermined length, the sensor sends a stop signal to control rolling or unrolling length of the electric roller shutter. Nevertheless, the sensor can only set a fixed rolling length or unrolling length and its rolling and unrolling speeds cannot be adjusted randomly.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.